Impact/Purpose:

The analysis of ambient air samples by X-ray fluorescence is a critical component in the interpretation of complex air quality studies. The data products generated by the XRF laboratory are therefore critical to protecting human health and the environment. Analysis of particulate matter by XRF contributes to the following outcomes:

1) By characterizing emissions from different source types EPA is able to ensure timely attainment of the national ambient air quality regulations (NAAQS).

2) These analyses assist in the development of models for predicting pollutant concentrations from source emissions, apportioning sources from air concentration data, and for predicting exposures from different source types. The goal of the aforementioned models is to accurately understand risk and the ways to reduce risks to human health and the environment.

3) Datasets generated by the X-ray fluorescence laboratory cross-cut several laboratories (NERL, NHEERL, NRMRL, etc.) and represent an important collaboration effort. The XRF laboratory products are therefore crucial in the integration of varied, and sometimes wide ranging, agency goals. It is these cross-cutting relationships that enable ORD to collectively assess pollutants which pose the greatest risk to global, regional, state and local populations.

Description:

This task is primarily concerned with the elemental characterization, by X-ray fluorescence analysis, of particulate matter (PM) collected during active or passive sampling of ambient air. The NERL X-ray fluorescence laboratory is an in-house research facility dedicated to quantitative analysis of PM samples on thin film media. This research laboratory is paramount to the analysis and quality assurance of PM samples collected both domestically and internationally.

Record Details:

Record Type:PROJECT

Start Date:10/01/2001

Projected Completion Date:09/01/2005

Record ID: 56213

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Project Information:

Progress :- FY02 Activities

Chemical and physical characterization of PM samples

After many months of evaluation, the Jordan Valley Inc. spectrometer was returned to the factory and the procurement contract was cancelled for non-performance, as part of a decision reached with two other EPA organizations that had also acquired one of these instruments. The Lawrence Berkeley Laboratory (LBL) XRF spectrometer was returned from LBL after undergoing extensive repair, and was operating routinely at the end of FY02. Extensive software work relating to LBL data acquisition and control functions was initiated. A new IAG was initiated with LBL for the feasibility of constructing a next-generation XRF spectrometer having an order-of-magnitude increase in detection sensitivity. XRF analysis was performed on samples from four projects: the World Trade Center disaster site, Hg-related ambient monitoring sites, Region 5 RARE motor vehicle tunnel study (also included neutron activation analysis), and audit samples from the PM2.5 Speciation Trends Network (STN).

Receptor model applications -- Application of the Positive Matrix Factorization (PMF) receptor model to human exposure data collected during the 1998 Baltimore Retirement Home Study was performed and prepared for publication.

The following products resulted from activities under this task in FY02:

Data Report: XRF analysis of PM2.5 samples from the World Trade Center disaster site.

Data Report: XRF analysis of PM2.5 samples from Hg-related ambient monitoring sites.

Data Report: XRF and neutron activation analysis of PM samples from Region 5 RARE motor vehicle tunnel study.

Data Report: XRF analysis of audit samples from the PM2.5 Speciation Trends Network (STN).

- FY03 Activities

The major XRF analysis effort was measuring more than 4000 PM samples collected during the 2000/2001 RTP Human Exposure Panel Study. Smaller efforts included analysis of samples from NARL/Montgomery (QC for OAQPS' PM-2.5 STN Network), Fort Hall Phosphorous Facility Study, Tampa/BRACE, and NHEERL.

A several month study of the laboratory air was conducted, motivated by a mysterious failure of QC standards during routine XRF analysis by the LBL system. The outcome was the remarkable finding that during the wintertime not only the laboratory air but apparently air throughout most of the whole facility contained NaCl aerosol at concentrations as large as 10 ug/m3. This was traced to the building humidification system that uses sprayed tap water to raise the wintertime humidity to comfortable levels. Without the prospect of a timely overall Facilities solution, the XRF Laboratory staff worked out a local solution to provide filtered cooling air to the XRF instrumentation, which solved the QC failure problem.

Refinement of software for the refurbished LBL x-ray spectrometer continued and reached a state of near-completion by the end of FY03.

An initial "outreach" initiative to recruit non-EPA clients involved discussion with Ted Russell (Georgia Tech) for analysis of samples from an Atlanta sampling network loosely associated with EPA's Atlanta Supersite. For various reasons an agreement was not reached, but a future one may be possible. Discussion of a CRADA with Cooper Environmental Services (CES) was initiated. The CRADA would involve evaluating EPA Spectral Deconvolution software for possible use in CES commercial instruments. Phil Hopke (Clarkson U.) has also expressed interest in acquiring this software.

By the end of FY03 work under the IAG with LBL had demonstrated that construction of a new XRF system with significantly increased sensitivity was feasible. Consequently, a decision was made by HEASD Management to proceed with the construction phase of the IAG.

Remaining work previously done under this task in FY02 was moved to new tasks that were initiated in FY03: organic measurements including

Relevance :This task supports GPRA Goal 1 (Clean Air) and FY06 APG 189. The XRF laboratory analytical activities under this task not only support source apportionment modeling, but also provide an analytical component to NERL's human exposure program, in furnishing a basic level of PM chemical characterization of field samples. The analytical data generated in this task are integral to many exposure and implementation projects, and their associated long term goals.

A cross-laboratory collaboration between the NERL XRF lab and several other EPA labs (e.g., NHEERL, NRMRL) has been established. NERL has made a notably important stride in integrating their XRF research facility with other EPA laboratories. In turn, the XRF research facility is directly contributing to broader agency goals in order to meet the needs of a dynamic and ever-changing global environment.

It is the goal of the NERL XRF laboratory to continue to be on the cutting edge of technology in environmental analysis. This goal unequivocally enables partnering researchers to better identify and quantify risks posed by anthropogenic and natural source emissions. As such, the role of the NERL XRF research facility is critical in mitigating exposures in a technically sound and cost effective manner in order to meet EPA's mission of protecting human health and the environment.



Clients :NERL, NHEERL, NRMRL, OAQPS, NAREL (Montgomery)

Project IDs:

ID Code :9572

Project type :OMIS